Welcome to HVAC-Talk.com, a non-DIY site and the ultimate Source for HVAC Information & Knowledge Sharing for the industry professional! Here you can join over 150,000 HVAC Professionals & enthusiasts from around the world discussing all things related to HVAC/R. You are currently viewing as a NON-REGISTERED guest which gives you limited access to view discussions

To gain full access to our forums you must register; for a free account. As a registered Guest you will be able to:

Participate in over 40 different forums and search/browse from nearly 3 million posts.

Honeywell 8580 WF - How intelligent is the smart response feature?

Hello everyone,

I have a multi-stage heat pump (Lennox XP14 with electric furnace as aux heat).

I'm from Montreal, Canada, meaning that winter temperature ranges between -40F and 50F. Since the thermostat does not know about outdoor temperature until the heat pump sends signal for aux heat, I'm wondering how intelligent is the smart response feature on my Honeywell 8580 WF.

I've programmed the daytime temperature to 60F since I'm not home, and 70F from 3PM. When outdoor temperature is at the heat pump efficiency boundaries (ex.: 18F), the system could in theory still make full use of the heat pump and avoid the aux heat by starting the heat pump quite earlier (ex.: 2 hours earlier). In theory, this would still save energy. But if it's not smart enough to predict this, it'll constantly request aux heat everyday at ~2:30PM because it could not recover quickly enough.

Is it smart enough to start ~2 hours earlier on cold days and avoid aux heat? I wouldn't see how, because there's no outside sensor directly connected to it. It only knows about it when the heat pump starts.

If it's not smart enough, should I simply leave it at 70F all day long to avoid using aux heat?